Abstract: Systems, apparatuses, and methods are described for synchronizing output of a plurality of user devices. An immersive experience for users may be provided by mapping what the users are watching into functionalities of the user devices. Manifest files may comprise information determined for audio and/or video features of segments of audiovisual content. The manifest files may be used by secondary user devices to output visual effects in synchronization with output of audiovisual content by a primary user device.